PALEONTOLOGY OF NEW-YORK 
ONEIDA CONGLOMERATE. 
The Oneida conglomerate marks, in a most decided and unequivocal manner, the limit between 
the lower and middle portions of our system. Its wide extent, and, in many places, its extra¬ 
ordinary development entitle it to rank as a formation of great importance. It is true that in 
Western New-York, and in the Western States, it is comparatively unimportant; but when we 
pass to the southeast and to the south by the shores of the Hudson, and thence into New-Jersey, 
Pennsylvania and Yirginia, this formation becomes very powerful, forming distinct topographical 
features. As examples of this we may instance the Shawangunk mountain in the southern part 
of New-York, and the extension of the same range in New-Jersey in the Blue or Kittatiny 
mountain range, which, in its southern extension, crosses the Delaware river at the Delaware 
water-gap, and thence through Pennsylvania and the western part of Maryland into Virginia. 
There are also numerous minor points, in Pennsylvania and Virginia, where this rock forms 
distinct and prominent features in the topography of the country. 
In the regular ascending order, the Oneida conglomerate succeeds the Hudson-river group. 
It sometimes rests directly upon the shales of that group, as in Herkimer county • or succeeds 
a fine-grained gray sandstone, which may be regarded as terminating the Hudson-river group, 
and forming a more natural passage into the conglomerate*. , 
I have not been able to recognize any fossils in this rock : indeed its materials are of such 
character that fossils could scarcely be preserved, and the conditions under which it was formed 
were not favorable to the development of organic existence. 
A few fragments of what appear to be marine plants have been seen in this rock, but in all 
too imperfect to be of any importance. 
* In Herkimer and Oneida counties, this conglomerate is closely associated with the beds of the Clinton group 
which immediately succeed it; and being there of coarse materials, it would readily be confounded in one group with 
the conglomerate. In the southern part of Herkimer county, the shales of the Hudson-river group are separated 
from the sandstones and ore beds of the Clinton group only by the Oneida conglomerate, which has but a very in¬ 
considerable thickness. Still farther east, along the base of the Helderberg, where the Clinton, Niagara and 
Onondaga-salt groups are very thin, the Oneida conglomerate is absent, and the shales and sandstones of the Hudson- 
river group rise to within a few feet of the Tentaculite limestone or Water-lime group. 
[ Paleontology — Vol. ii.] 1 
